Star Wars: The Last Jedi feels like a Star Wars MMORPG novel. This is a curious statement because we have had lots of Star Wars MMORPG novels and none of them felt like this. The Old Republic tie-in fiction is more or less identical to regular Star Wars fiction with the caveat it is rare that it's allowed to finish its story.
The Ruins of Dantooine, made for the Galaxies MMORPG, is widely considered to be one of the worst Star Wars novels of all time. The Last Jedi, by contrast, is a very fun novel but it feels more like Galaxies and The Old Republic than any of the other novels ever did.
Indeed, I'd argue it's not necessarily an online role-playing game that The Last Jedi feels like. Instead, it feels like a roleplaying-game period. I played literally hundreds of hours of Star Wars: The Roleplaying Game as well as its sequel, Star Wars SAGA without the benefit of computers. A more or less typical party of characters would consist of a guy wanting to be a Jedi, smugglers, droids, and the obligatory Twilek love-interest.
Our heroes would tool around the galaxy, conduct various raids against the Empire on behalf of the Rebel Alliance, and do their very best to avoid the attentions of Lord Vader. Because Darth Vader couldn't be killed due to the movies, or so fanboy logic went, he was depicted as an invincible juggernaut of destruction.
You could thwart his schemes and plans but not actually stop the villain himself. When you wanted your Jedi Knight to face a Dark Jedi, you sent them up against the Imperial Inquisition. The Imperial Inquisitors, created by West End Games, were Darth Vader-lite types who were omnipresent Dark Siders after your heroes.
In a weird way, The Last Jedi is also a throwback to the Pre-Prequels Star Wars universe. There's no hints of the emotionally unstable Anakin beneath Darth Vader's mask. Instead, he's treated as an unstoppable force of nature akin to his handling in A New Hope and The Empire Strikes Back. The Empire is all-pervasive and tyrannical with freedom-loving people across the galaxy desiring to overthrow it. The Rebel Alliance doesn't exist yet but our heroes work with miniature versions of it on numerous worlds.
The Star Wars RPG universe had ample room for other heroes than Luke, Han, and Leia with dozens of low-level or wannabe Jedi Knights tooling around. Jax Pavan isn't really a threat to the supremacy of the Dark Lord like, say, Starkiller because despite being a fully trained Jedi--he's ridiculously outclassed by Vader. Were Luke Skywalker and Jax to ever meet up, it's likely untrained Luke would be more powerful than him. That's how the RPG worked too, with Rebellion-Era Luke possessing ridiculously high Force stats despite his untrained nature.
This "classic" of the Star Wars universe is important to bring up because I suspect whether you like RPGs or not will determine what you think of this novel. It feels very much like someone novelizing a campaign. There's a bunch of Maguffins, exotic locations, rescue missions, guest-stars, and temptations for Player Characters to hang themselves with (also known as the "Deck of Many Things" ploy). Jax Pavan goes to Topwara, Dathomir, Coruscant, Mandalore, and Darth Vader's secret fortress. He meets with Prince Xizor, Lord Vader, and members of the Singing Mountain clan. Even the mission, rescue an important Rebel General, is the kind of thing West End Games used to put in their adventure modules.
Overall, I really enjoyed The Last Jedi but I have complaints. One of them is the death of Laranth. There's a phenomenon in comics known as "Women in Refrigerators" and this is an example of that. Basically, Laranth's death exists solely so Jax Pavan can have some character development by having him react to her death. Given Laranth was an interesting character in her own right, being a Jedi Gunslinger, this only makes it more troublesome. Her death also comes off as somewhat perfunctory as if she didn't warrant something suitably epic.
I also think the rescue of Whiplash's leader is too low-stakes for a 400+ page novel. Whiplash is a Rebel Cell, not the Rebel Alliance and I would have preferred something more epic like Jax Pavan wanting to blow up a Star Destroyer or the Inquisition's base. Some members do want to achieve something huge but well, we know what happens with this plan the moment someone describes what the objective is.
Curiously, despite its old school feel, the book ties together the "modern" EU with The Clone Wars Animated series in a way which feels seamless. Mandalore is under the control of Death Watch and selling its citizens as slaves, the Dathomir have large number of Zabrak-Human hybrids even in the Singing Mountain clan, and there's no sign of any real continuity hiccups. It makes me want Michael Reaves to have Jax hook up with the Mareks on Kashyyyk or jump ahead to the point Starkiller can hang out with Pavan.
In conclusion, I really liked The Last Jedi but it's crunchy genre fiction at its crunchiest. You won't miss out on anything by not reading this book but it's enjoyable enough if you want something Star Warsy for your diet. I hope they make another couple of books in the series as I have no objections to the character or his continuing adventures.